Method of producing a ring gear and flywheel assembly

ABSTRACT

There is provided a method for producing a ring gear and flywheel assembly, which method includes the use of a shuttle arrangement for moving successive ring gears through a high frequency induction heating and quench hardening station, a lower frequency tempering station, and a station wherein the heated ring gear is magnetically held and shifted over the outer periphery of an aligned flywheel preparatory to cooling of the ring gear to shrink fit it upon the flywheel.

1451 Dec.4, 1973 United States Patent Cachat i 244 22 mm an N" e" vlmru uman S d Cb nmm ey EF DR 00022 46777 99999 1111] uuwww 1 METHOD OF PRODUCING A RING GEAR Primary ExaminerRichard J. Herbst Assistant Examiner-James R. Duzan [21] Appl. No.: 273,525 Att0r ney.1ames H. Tilberry et al.

[52] US. 29/447, 148/147, 148/150, [57] ABSTRACT 219/;059, 219/1079 There is provided a method for producing a ring gear 51 lm. 823 11/02 and flywheel assemblywhich method includes the use 58 Field of 219/10.59, 10.79; a Shuttle arrangement for moving Successive g 14 47 150, 29/447; 294/65 5 gears through a high frequency induction heating and quench hardening station, a lower frequency temper- References Cited I ing station, and a station wherein the heated ring gear UNITED STATES PATENTS is magnetically held and shifted over the outer periphery of an aligned flywheel preparatory to cooling of the ring gear to shrink fit it upon the flywheel.

j S'CIaiIns, 13 Drawing Figures PAIENIEUBEEM H sum ESP 5 METHODOF PRODUCING A RING GEAR AND a 2 costly than prior methods, for performingthis function. These and other objects and advantages will become apparent from the following description taken in con may be used for hardening and mountinga ring gear onto various types of mountingstructures.

Internal combustion engines generally include a flywheel mounted upon the end of a'crankshaft, which flywheel includes a peripherally extending ring gear for engagement with a pinion on the starting motor. The

ring gear and flywheel are produced separately and then assembled into aunit. Before being assembled, the ring gear is heated and quench hardened to provide for improved wear characteristics. Generally, after this hardening operation, the ring gear. is tempered to remove surface stresses and reduce brittleness in the individual teeth around the gear.

a In the past, the, ring gear was inductively heated and quench hardened in a, separate station. The hardened gear was then removed and tempered in an appropriate furnace. After being tempered, the ring gear was secured onto the outer periphery of an appropriately proportioned flywheelL-All of these operations require a substantial amount of manual handlingof both the flywheel and the ring gear. This couldresult in damage and definitely resulted in relatively high labor costs in the production of the flywheel and ring gear assembly.

The present invention relates toa method of producing a flywheel and ring gear assembly which method requires a relatively minor amount of manual handling and generally reducesthe processing time and' steps in the production of this assembly. a I

In accordance with the present invention, there is provided a method of producingan assembly including a' ringgear having a peripheral cross-section and se" cured onto the outer periphery of a generally circular support base, suc h as a flywheel. Th is method includes the steps of providing a shuttle having firstand second; ring gear receivingnest s, positioning a hardenedring gear in the first nest and an unhardened ring gear. in the second nest, moving the shuttle into aposition with the first nest aligned with a temperingdevice and the second nest aligned with a. hardening device, inductively heating and quench hardening the unhardened ring gear, inductively heating the hardened ring gear to a tempering temperature, placing the hardened ring gear Conveyor F shifts the ring gear D from the station Ill i FIG. 2 is an enlarged, schematic view junction with the accompanying drawings in which:

FIG. l is a pictorial view illustrating an apparatus for performing the'preferred embodiment of the present invention; V

taken generally along line 2-2 of FIG. 1;

' FIG. 2A is a'view similar to FIG. 2 showing an'operation of the apparatus illustrated in FIG. 1;

FIG. 3 is an enlarged, schematic view taken generally alongline 3-3 of FIG. 2;

.FIG. 4 is a schematic view taken generally along line 4-4 of FIG. 2 i

FIG. :5 is a view similar to FIG. 4 illustrating operatingcharacteristics of the structure'disclosed therein;

FIG. 6 is a schematic, partial, enlarged crosssectional view taken generally along line 6-6 of FIG. 1;

.FIGS."6A6D are progressive views similar to FIG. 6 illustrating operating characteristics of the structure shown therein; I

FIG. 7 is an enlarged, partial, schematic crosssectional view taken generally along line 77 of FIG. 1; and, I FIG.- 8 is a flow chart for the parts as they move through the apparatus illustrated in FIG. I

Referring now to the drawings wherein the showings are for therpurposeof illustratinga preferred embodie ment of the invention only,- and not for the purpose of limiting same, FIG. 1 showsan apparatus A for producing an assembly'B fonned from joining flywheels C and ring gears D. This apparatus includes four stations I, II, III and IV which combine to perform the assembly operation. Station I includes a stack of ring gears D and provides a ring gear supply for the apparatus A. Station II inductively heats'the ring gears with a'high frequency and then quench hardens the heated ring gear. Station III heats the ring gear to a tempering temperature with a lowfrequency alternating currentto produce a tempered ring gear which is shifted to station IVan d assembled onto a flywheel C beforeit has cooled. At station IV, the ring gear is'cooled so that'it" shrinks over the flywheel'and forms a' unitary assembly B. As schematically illustrated in FIG. 8, a plurality ofdiverse conveyors are employed forshifting the various components through'the apparatus A. Conveyor'E moves the ring gears successively through stations I, II and III.

to the station IV where it is assembled onto its flywheel 1 C. Thereafter, conveyor G shifts the assembly from staprovision of a method for producing a ring gear and flywheel assembly, which method reducesthe handling of the ring gear and flywheel. v

Anotherobject of the present invention is the provision of a method for producing a ring gear and flywheel I assembly, which method requires a minimum of equipment and floor space.

Yet another object of the present invention is the tion IV. Aconveyor H supplies flywheels C to the apparatus A and specifically to station IV. Conveyor .I direets the completed assembly B from the apparatus A.

-In operatiomthering gears D are stacked at station I, and a succession of flywheels C are placed onto conveyor H. An operator at the entrant end of conveyor H places these flywheels in position and removes completed assemblies B from the exit side of conveyor .l

"Du'ring the heating operation at station II, the ring gear D is inductively heated to a temperature above the hardeningtemperature which may be in the rangeof ring, gear has decreased to below approximately 3 500600F, the ring gear is placed over the outer periphery of the flywheel C and is then quenched at sta tion IV. This shrinks the ring gear over theouter periphery of the flywheel and finalizes theintended as sembly. The ring gear, after tempering, has a hardness of approximately 55-60 Rockwell C. i

Referring now in-more detail to the apparatus A, FIGS. 2, 2A, 3 and'4 illustrate the first three stations of the apparatus. Station [which is essentially a supply stack of ring gears D includes a fixed support and a support 12, which is adjustabletoaccommodate various size ring gears. Station II includes an inductor hav. ing an internal periphery generally matching the outside periphery of ring gear D andconnected to a high frequency power supply 22, as schematically shown in FIG. 3. This power supply has an output frequency generally exceeding 3 ,000 cps so that the ring gear when positioned, as shown in FIG. 2A, can be inductively heated by'energizing inductor 20. Above the inductor there is provided'a generally circular quench body 30 having downwardly facing holes 32 for directing a quenching fluid against the inductively heated ring gear D. Station Il also'includes a chuck 40 having a lower head 42 which expands outwardly to grip the innerperiphery of a ring gear, a reciprocally mounted shaft 44 and a motor means 46 for rotating the chuck and ring gear inside of the inductor 20. Surrounding the components so far described, there is provided a housing 50 having a plurality of transparent windows 52.

In operation of station II, as best shown in FIG. 2, a ring gear D is positioned directly below chuck 40. The chuck then moves downwardly into the ring gear, and head 42 expands gripping the ring gear. Thereafter, the ring gear D is moved upwardly, as shown in FIG. 2A, and is rotatedby motor means 46. Whilebeing rotated, power supply 22 is activated to energize inductor for inductively heating the ring gear D. After sufficient time to raise the ring gear above the quench hardening temperature, supply 22 is deactivated and a quench'liquid is directed through holes 32 against the heated ring gear. This quench hardens the ring gear to -a hardness of generally 60-65 RockwellC. Thereafter, the rotashifts the movable portion 64 downwardly into engagement with the fixed portion 62, as shown in FlG..2A. Low frequency current is then passed through winding 80 and the ring gear acts as a secondary winding which conducts current and causes heating of the. ring gear. As illustrated, the nest. 90- vis electrically nonconductive; however, the nest may be conductive because there is no circuit created in this U-shaped nest. A heat insulation material could be used to prevent an undue-conduction of heat from the ring gear. The ring gear is heated at station III to a temperature in the general range of 700l ,100.F which causes tempering of thehardened ring gear to a resultant hardness of approximately 55-60 Rockwell C.

Conveyor E, includes a shuttle 100 having a relatively thick rear portion 102 and a thinner forward portion :104. A nest defined by V-shaped wall 110 and a tion of chuck 40 is discontinued and shaft 44 moves the I chuck to the downward position for release of the hardened ring gear.

' Referring now'to station'lll, there is provided an outer housing 60 in which there is a stationary portion 62 of a laminated core and a movable portion 64 of this core. The core is shiftable between position shown in FIG. 2 and the position shown in FIG. 2A to alternately provide a gap 66 between the two portions'of the core. Movable core portion 62 is secured onto a support 68 which is reciprocated selectively by a cylinder 70 secured to the upper wall of the housing 60. As is schematically illustrated, a primary winding 80 is provided around oneportion of the laminated core. In the illustrated embodiment, this winding is secured onto the movable portion 64; however, it may be. placed on the stationary portion 62. The powersupply 82 energizes the winding 80 with a low frequency alternating current, such as 50-60 c.p.s. Between the core portions there is provided a movable nest'90 having a U-shaped opening 92 and a corresponding U-shaped support ridge 94. A hardened ring gear is moved into the nest 90 and rests upon the support ridge 94 when the core portions 62, 64 are opened. Movement of the ring gear 1 is provided through gap 66. Thereafter, cylinder 70 nest formed by V-shaped plate 112 provide two supporting and moving structures for ring gears D as the shuttle is reciprocated between side supports 120, 122 having supporting ways 124, 126, respectively. During this reciprocation the ring gears rest upon the side supports which are generally aligned with portion 104. Cylinder having a fixed bracket 132 and a shuttle supported bracket 134 is used for selectively reciprocating the shuttle 100. I

When shuttle 100 is in the rearward position shown in FIGS. 2 and 4, a ring gear within the nest formed by V-shaped plate 112 is at station II. In addition, a ring gear in station I has dropped into the thinner portion 1040f the shuttle 100. Cylinder 30 is then actuated. to shift the shuttle '100 to the left, as shown in these figures, which moves a hardened ring gear from station II to station III. At the same time, the ring gear within the nest formed by V-shaped wall 110 is shifted from station I to station II. The thicker portion 102 of shuttle 100 is then located under the stack'of ring gears within station I. Wall 112 holds'the ring gear in the proper position within the U-shaped opening 92 while-the ring gear is being heated in station Ill.- At the same time, chuck 40 raises the ring gear at station II for heating and hardening as previously described.

After the ring. gear atstation III hasbeen heated to the tempering temperature. and the ring gear at station II has been raised, shuttle.l00.can bemoved rearwardly to the position shown in FIG. 2, Thereafter, station Ill may be unloaded in a'manner to be described later and the hardened ring gear at station II is again placed within the nest defined by V-shaped wall 112. At the same time, the thicker portion 104 disengages the bottom-of the'stack station I allowing another ring gear to drop into the nest formed by V-shaped 'wall 110. The cycle is then repeated to successively harden and temper ring gears D. 3 I

Referring now to FIGS. 6 and 6A-6D, the operation at station IV is illustrated. This station includes a reciprocal plate having downwardly extending magnets To bring the rear gear D from station III to station IV, there is provided an appropriate conveyor device schematically illustrated as conveyor F and including supporting and guide rails I60, 162 extending from station III and supporting nests 90 for reciprocal movement between these stations. To provide further support,it is possible to include a plurality of guide rollers 164, shown in FIG. 2,wh'ich ride in a track extending beend of the conveyor. Thereafter, pegs 200 move upwardly' engagingthe central opening of each of three flywheels. Cylinder 220 then shifts the rod 202 to the left as shown in FIG. 7. This brings one flywheel into the proper position within station IV. Thereafter, cams 210-216 are rotated to the phantom position allowing I the rod 202 to move downwardly releasing all the tween these two stations. A cylinder 170 having a fiired end 172 and a movable end 174 is employed for selectrated in FIG. 6A is below the Curie Point;'therefore,

the magnets 142 magnetically couple themselves with the ring gear. These magnets have sufficient magnetic strength to hold the weight of the ring gear as the cylinder 144 moves plate 140 upwardly from the nest 90 and removes the ring gear therefrom. This is shown in FIG.

6B. Thereafter, nest 90 is returned to station III, as

shown in FIG. 6C. At this time, cylinder 144 moves plate 140 downwardly to position the ring gear around the appropriate periphery on the flywheel C aligned below the ring gear and supported on rails 150, 152. Plate 140 remains in this position to hold the ring gear as a coolant is directed through nozzle 154for. cooling the-ring gear and allowing it to shrink into ashrink fit a connection with theflywheel C. t a 1 As shown in FIG. 6D, the plate 150 is then movedupwardly'by cylinder 144. At this time, the magnets 1 42 :are rotated to the solid lineposition which again enflyWheeIs Thereafter, cylinder 220 moves to the right into the phantom line position. Then, cams 210-216 gages the pegs 200 with three successive flywheels.

. This disengages the flywheels at station IV. This successdo not have sufficient magnetic strength to lift both the ring gear and the attached flywheelytherefore, the

sembly B remains atstation IV. Of course, magnets142 m be tfm nt which are de-energized to release the'ring gearfro m its" position): Since the magnets hold the ringg'e'ar in place-during the quenching," 1

Propel' lignmtflm fthe ring gear on the flywheel i maintained.

Conveyor G including transversely'extending rails 180 and a cylinder 182 having aplunger184then' ejects the assemblyB from station IV and onto conveyorl. This requires a release of the workpiece from Referring now to FIG. 7, more details of a conveyor for moving the flywheels C are illustrated. Of course,

various conveyors could be used for this purpose. In accordance with the illustrated embodiment, rod 202 is cams are rotated from the solid line position to the dotted line position, rod 202 is moved vertically downsupported on cams 210,212, 214 and-2l6. When these wardly and pegs200 disengage from openings in the flywheels C. While in the downward position-, a cylinder 220 having a fixed end or bracket222 and a m'ovable end 224 secured to the rod 202-can reciprocate the rod and pegs from one position to another in a longitudinal direction; Consequently, in operation of this sive reciprocation and longitudinal movement of rods 202 progressively shifts flywheels into station IV where they areproividedwith a ring gear. Rails 150, 152 support thesesuccessively moving flywheels so that they do not move downwardlyxas. rod.202 is moved in the I be appreciated that various modifications may be made in these elements without departing from the intended spirit and scope of the invention as defined in the appended claims.

Having thus defined my invention, I claim:

l. A method of producing an assembly including a ring gear havinga peripheral cross section and secured ontothe outer periphery of a generally circular-support base, said method comprising the steps of:

a. rotating said ring gear at a first station} b. inductively heating said rotating gear by' a high frequency inductor to a temperature above its hardening temperature; c. quenching said inductively heated workpiece; d. moving saidworkpiece to a second station;

e. placing a transformer. corearound the peripheral ;.cross sectionof saidring gear; 1. e 1

f. energizing said core; with a low fr'equency current until said ring gear isheated to a tempering temper- 4. The method as defined a. claim 3 wherein said SC- core from aroundlsaid peripheral lected temperature is above about,6Q0F.

5. The method asdefined in claim 1 wherein said selected temperature is aboveabout 600F. v

6. A method of producing an assembly including a ring gear'having a peripheral cross section and secured onto the outer periphery of a generally circular support 'base, saidmethod includes the steps of:

conveyor an operator places a flywheel C at the right 7 a. providing a shuttle having first and second'ring gear receiving nests;

.ature substantially below said hardening temperaring gear whereby said ring gear b. positioning a hardened ring gear in said first nest and an unhardened ring gear in said second nest;

0. moving said shuttle into a position with said first nest aligned with a tempering device and said second nest aligned with a hardening device;

d. inductively heating and quench hardening said unhardened ring gear;

e. inductively heating said hardened ring gear to a tempering temperature;

f. placing said hardened ring-gear around said support base before it has cooled below a selected temperature; and,

g. cooling said hardened ring gear whereby it is shrunk into said support base.

7. A method of producing an assembly including a ring gear having a peripheral cross'section secured onto the outer periphery of a flywheel, said method comprising the steps of: I

a. providing a shuttle having first and second ring gear receiving nests and movable between a first position with said first nest at a first station and said second nest at a second station. and a second position with said first nest at said first station and said second nest at a third station;

b. placing a first ring gear in said first nest at said first station where said shuttle is in said first position; 0. shifting said shuttle to said second position with said first nest and first ring gear being at said second station; 1 d. lifting said ring gear from said first nest;

e. inductively heating said first ring gear withian inductor energized by a high. frequency current;

f. quench hardening said first ring gear;

g. shifting said shuttle into said first position;

h. placing a second ring gear into said first nest and placing said first ring gear into said second nest;

i. shifting said shuttle into said second position with said first ring gear at said third station and said second ring gear at-said second station;

j. inductively heating said first ring gear with a surrounding transformer core energized by a low frequency;

k. then placing said heated first ring gear around the outer periphery of said flywheel; and,

l. cooling said ring gear whereby said ring gear is shrunk onto said flywheel.

8. A method of assembling a heated ferromagnetic ring gear onto the outer periphery of a flywheel, said method comprising the steps of;

attestin id/ ins. r. a.. t n r b w about WP and below the Curie Point of the ring gear; a

'b. shiftingsaid heated ring gear below a movable magnetic element;

{c.holdirig said ring gear onto said magnetic element; 1

'd.'supporting a flywheel below said ring gear;

e. moving said element downwardly to position said heated ring gear around said outer periphery of saidflywheel; I -f I f. holding said ring gear in placeon said outer periph- 'y; i a g.. simultaneously cooling saidring gear wherebyit is shrunk onto said flywheel. i 

1. A method of producing an assembly including a ring gear having a peripheral cross section and secured onto the outer periphery of a generally circular support base, said method comprising the steps of: a. rotating said ring gear at a first station; b. inductively heating said rotating gear by a high frequency inductor to a temperature above its hardening temperature; c. quenching said inductively heated workpiece; d. moving said workpiece to a second station; e. placing a transformer core around the peripheral cross section of said ring gear; f. energizing said core with a low frequency current until said ring gear is heated to a tempering temperature substantially below said hardening temperature; g. removing said core from around said peripheral cross section; h. placing said ring gear over said support base while said ring gear remains heated above a selected temperature; and, i. then cooling said ring gear whereby said ring gear is shrunk onto said support base.
 2. The method as defined in claim 1 wherein said hardening temperature is above 1,700*F.
 3. The method as defined in claim 2 wherein said tempering temperature is in the approximate range of 700*-1,100*F.
 4. The method as defined in claim 3 wherein said selected temperature is above about 600*F.
 5. The method as defined in claim 1 wherein said selected temperature is above about 600*F.
 6. A method of producing an assembly including a ring gear having a peripheral cross section and secured onto the outer periphery of a generally circular support base, said method includes the steps of: a. providing a shuttle having first and second ring gear receiving nests; b. positioning a hardened ring gear in said first nest and an unhardened ring gear in said second nest; c. moving said shuttle into a position with said first nest aligned with a tempering device and said second nest aligned with a hardening device; d. inductively heating and quench hardening said unhardened ring gear; e. inductively heating said hardened ring gear to a tempering temperature; f. placing said hardened ring gear around said support base before it has cooled below a selected temperature; and, g. cooling said hardened ring gear whereby it is shrunk into said support base.
 7. A method of producing an assembly including a ring gear having a peripheral cross section secured onto the outer periphery of a flywheel, said method comprising the steps of: a. providing a shuttle having first and second ring gear receiving nests and movable between a first position with said first nest at a first station and said second nest at a second station and a second position with said first nest at said first station and said second nest at a third station; b. placing a first ring gear in said first nest at said first station where said shuttle is in said first position; c. shifting said shuttle to said second position with said first nest and first ring gear being at said second station; d. lifting said ring gear from said first nest; e. inductively heating said first ring gear with an inductor energized by a high frequency current; f. quench hardening said first ring gear; g. shifting said shuttle into said first position; h. placing a second ring gear into said first nest and placing said first ring gear into said second nest; i. shifting said shuttle into said second position with said first ring gear at said third station and said second ring gear at said second station; j. inductively heating said first ring gear with a surrounding transformer core energized by a low frequency; k. then placing said heated first rinG gear around the outer periphery of said flywheel; and, l. cooling said ring gear whereby said ring gear is shrunk onto said flywheel.
 8. A method of assembling a heated ferromagnetic ring gear onto the outer periphery of a flywheel, said method comprising the steps of: a. heating said ring gear to a temperature above about 600*F and below the Curie Point of the ring gear; b. shifting said heated ring gear below a movable magnetic element; c. holding said ring gear onto said magnetic element; d. supporting a flywheel below said ring gear; e. moving said element downwardly to position said heated ring gear around said outer periphery of said flywheel; f. holding said ring gear in place on said outer periphery; and, g. simultaneously cooling said ring gear whereby it is shrunk onto said flywheel. 